218 J. W. SPEXCER SUBMARINE VALLEYS 



covered with it as to prevent the recover}^ of Tertiary deposits and estab- 

 lish the common origin of these plains with those existino^ in New Jersey. 



Some Valleys of the North Atlantic and adjacent Arctic Basins* 

 valleys between greenland and america 



The soundings beyond the Newfoundland banks are insufficient for 

 study. One line between Labrador and Greenland shows a rapid descent 

 from the continental shelf (here less than a thousand feet below sealevel) 

 to 5,220, and farther on to 9,732 feet, beyond which the descent is more 

 gradual to the depth of 12,196 feet, which is in the center of the arm of 

 the Atlantic basin between Greenland and the continent. Between 

 Greenland and the southern point of Baffins Land the depth is reduced 

 to 8,100 feet, and a little farther northward to 6,600 feet, though there 

 may be a deeper channel not made known. In latitute 66 degrees 

 the soundings are numerous and show fragments of the Greenland coastal 

 plain, even to a breadth of 70 miles, with a submergence of less than 

 300 feet, while the trough in Davis straits, except in narrow channels, is 

 reduced to 2,160 or 2,270 feet. Here is the col between the arm of the 

 Atlantic basin and Baffin bay, in which, nearby, are culs-de-sac, one 

 reaching to 3,996 feet, with the bay beyond, having a depth of 6,000 

 feet, and another 5,580 feet within the 1,700-foot contour line. The 

 soundings are moderatel}^ numerous and show magnificent fiords to 

 depths of 4,000 feet. While at first sight the soundings here suggest 

 that Baffin ba}^ is a distinct basin, yet upon second consideration, 

 owing to a considerable part of the bay having onl}^ a moderate depth, 

 this apparent form ma}^ be due to partial obstruction of the straits b}^ 

 glacial or iceberg deposits or to the soundings being insufficient to reveal 

 a restricted valle\^ beneath this narrowed arm of the sea. Some of the 

 deep tributary fiords, however, are not refilled with drift to the point of 

 distinction, as off Newfoundland and Norway. 



The maximum depth of the lower part of Hudson straits is unknown, 

 exce])t that it is more than 1,800 feet deep at several points, while sev- 

 eral hundred miles westward it is 1,200 feet, and Hudson bay, even near 

 its outlet, much less. The upper part of Hamilton inlet has a depth of 

 600 feet, but the coastal plain in front, much of which is shallow, is not 

 known to be covered by more than 200 feet of water. 



VALLEYS BETWEEN GREENLAND AND SCOTLAND 



The soundings in this belt are numerous and full of interest. While 

 there are many illustrations of the oceanic basin wherein the submarine 



*See the U. S. Hydrographic Charts, nos. 2lrt, 216, 318, 1531. 



